This invention relates generally to tool bars for use in track presses and more particularly to multi-pitch tool bars for receiving bushing and pin tools to engage pins and bushings of drive chains having different pitch and size.
Crawler or track laying tractors are widely used particularly for heavy duty work. The tracks employed in such tractors include ground engaging shoes or grousers removably secured to a drive chain driven over an idler sprocket by means of a driven sprocket. The drive chain includes a plurality of sections each adapted to receive a shoe. Each section includes a pair of side links spaced apart to receive the sprocket wheel teeth. Each section is pivotally joined to the next adjacent section by means of a cross pin and bushings. The side links of each section are relatively widely spaced at one end to receive the relatively closely spaced ends of the next side link. Bushings are press fit into the closely spaced ends while pins are press fit into the widely spaced ends of each pair to form the pivotable joint between sections.
Because of the nature and operation of tractors, the tracks are subjected to rapid wear and require frequent repair. Generally, for repair, the track is removed from the tractor by removal of a master pin and the track is laid out. In larger tracks the shoes or grousers are removed to expose the drive chain. In smaller tracks, they are not removed. In either case, the chain is then mounted on a track press and moved to present the links in succession to a work station which includes a jaw for holding spaced adjacent bushings of the chain in position as hydraulic rams move spaced pin and bushing tools mounted on a tool bar into cooperative relationship with the pins and bushings to remove the pins and bushings from the links to release the side links for disassembly. During disassembly, the chain is moved in the opposite direction and the pins and bushings are inserted by spaced pin and bushing tools.
The track press generally includes hydraulically driven tools on each side of the chain whereby to engage and remove or insert the pins and bushings from each side of the links in succession. The links are restrained from side movement by a jaw which includes spaced U-shaped grooves for receiving the bushings and orienting each section in a position whereby the advancing tools register with the pins and bushings. The jaw may be a retractable jaw which is retracted to advance the chain one section at a time to present the next section to the station or may be a fixed jaw where the chain is moved upwardly, advanced and then lowered to place the bushings in engagement with the jaw grooves. A typical track press with retractable jaws is described in U.S Pat. No. 3,075,346.
There are many models and sizes of track laying tractors manufactured by each of a number of manufacturers. The track size differs for different models, sizes and manufacturers. As a result, different sizes and pitch of pin and bushings tools are required to provide the proper pitch and size to engage the pins and bushings for the variety of tracks encountered. Different heights of the tool centerline are also required. Present day tool bars do not provide a large choice of pitches and sizes. In U.S. Pat. No. 3,075,346, there is shown and described a slotted tool bar which provides for adjustable pitch. However, the operator must carefully position the pin and bushing tools to assure proper pitch and position with regard to the associated chain. Tool bars are also available having spaced pairs of tool mounting holes disposed on a single centerline. A different tool bar is required for different size chains since the height centerline of the pins and bushings will be dependent thereon.